Textile filaments



July 16, 1963 A. H. M KINNEY 3,097,416

TEXTILE FILAMEN'I'S Filed Sept. 26, 1960 2 Sheets-Sheet 1 3 +20 LIJ m 8 0 0| 0.2 0.0 0.4 0.5 0. ENTOR ALFRED H. MCKINNEY %JM/ BY ATTORNEY July 16, 1963 A H McKlNNEY 3,097,416

TEXTILE FILAMENTS Filed Sept. 26, 1960 2 Sheets-Sheet 2 r/R INVENTOR ALFRED H. McKiNNEY ATTORNEY United States Patent 3,097,416 TEXTILE FILAMENTS Alfred H. McKinney, Chester, Pa., assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed Sept. 26, 1960, Ser. No. 58,342 Claims. (CI. 2882) This invention relates to textile filaments and fibers. More particularly, it relates to multilobal filaments and fibers prepared from synthetic polymers.

Textile filaments prepared from synthetic polymers, e.g., from polyamides and polyesters, have a characteristic gloss or sheen which while being very desirable in certain products is undesirable in others. In many apparel fabrics as well as floor covering materials a subdued luster rather than a gloss or sheen is preferred. In addition, due to the somewhat transparent nature of such filaments, textiles prepared from them do not possess the degree of hiding or covering power required in certain fabric constructions. By modifying the fiber cross section it has been possible to improve covering power. However, such modifications have resulted in a loss in resistance to soiling as well as other desirable properties. It has been recently discovered that by utilizing filaments of a particular cross section the gloss or sheen can be eliminated and a sparkling luster provided. Such highluster filaments as those described in US. Patents 2,939,201 and 2,939,202 also provide superior covering power as well as outstanding resistance to soiling. However, in order to obtain a subdued luster from the filaments described in these patents, it has been necessary to add dellusterants to the polymer from which the filaments are prepared.

The addition of delusterants to the polymer is accompanied by undesirable results. For example, the use of conventional delusterants, such as titanium dioxide, in filamentary structures results in poor light stability of the structures, particularly those containing large quantities of delusterant. Also, the light-fastness of certain dyes on many polymeric materials is impaired by presence of the delusterants and, furthermore, upon exposure to sunlight the filaments tend to develop an undesirable chalky appearance. The presence of delusterants in the polymer also reduces color clarity and optical depth of the filaments, giving the fabrics a chalky, washed-out appearance. Due to the abrasive nature of the delusterant particles, excessive wear in processing equipment is experienced. In addition, uniform distribution of the delusterant in the polymer is dilficult to achieve.

It is, therefore, an object of the present invention to provide novel filaments from synthetic polymers which exhibit a subdued luster, excellent covering power, and high resistance to soiling. A more specific object of this invention is to provide filaments of synthetic polymers having a trilobal cross section which exhibit the aforementioned properties without the incorporation of delusterants in the polymer. Other objects will appear herelinafter.

The objects of this invention are accomplished by providing novel filaments and fibers from synthetic polymers which have a cross section consisting of three integrally joined, substantially symmetrical lobes. By maintaining the cross-section configuration within certain parameters to be described in detail later herein, textiles, prepared from the products of this invention exhibit outstanding and unique optical properties as well as improved resistance to soiling. The resistance to SOlllIlg includes not only the ability of the filaments and pickup of soil but also soil-hiding ability attributable to the unique optical properties. The unique optical properties provide a high degree of cover and a pleasing subdued luster.

The lobes of the filaments of this invention are located with substantial symmetry about a central point. Each lobe has a curved terminal portion or tip generated by a radius, the origin of which is along the line of symmetry of the lobe. The curved terminal portion or tip of the lobe is connected to adjacent tips by side portions which are generally curved but may have a limited length of essentially straight side which connects the curved portion to the tip. The lobe is further defined by a lobe or arm angle formed by extending the straight side portions, when present, or lines which are tangent to the curved side portions and the terminal portion of the tips at their point of intersection.

In general, the filaments of this invention may be prepared by extruding molten polymer or a solution of the Spinning conditions must, of course, be varied depending on the particular synthetic polymer being extruded. The conditions should be controlled to provide filaments having a substantially uniform cross-sectional shape along their length,

The present invention will be more fully understood by reference to the following detailed description and accompanying drawings, in which:

FIGURE 1 is an enlarged representation of a cross section of a filament of this invention;

FIGURES 2 and 3 are graphs showing the areas which define limits of the parameters of the cross section of the filaments of this invention; and

FIGURE 4 is an enlarged representation of a spinneret (l) The ratio of the tip radius r of the lobe to the radius R of a circle a having a center c circumscribed about the tips b of the lobes;

(2) The arm or lobe angle A formed by projecting the common tangents, i.e., straight portions de and d'e' of each lobe, when these are present; or, when no straight side is present, the angle formed by projecting the common tangents of the arcs g and g of radius r; forming the sides of a lobe and the arc of radius r; forming the lobe tip;

(3) The ratio of the length f of the essentially straight portion (1-2 or the ratio of the length f of the essentially straight portion d'-e' to the radius R of the circumscribed circle;

(4) The ratio of the radius r of the arc g to the radius R;

(5) The ratio of the radius R to the radius R of a circle having center is inscribed within the cross section, referred to herein as the modification ratio M.

For convenience, I have chosen to define my invention in terms of relationships (1), (2), (3), and (5), i.e., the tip radius ratio the arm angle A, the straight side ratio and the modification ratio M.

In accordance with this invention, the tip radius ratio must be within the range from about 0.05 to about 0.4 the arm angle must be within the range from about to about +40", the modification ratio must be within the range between about 1.9 and about 4.0, and the straight side ratio must be within the range between about zero and about 0.7.

It will be apparent by referring to FIGS. 2 and 3 that only certain combinations of the aforementioned perameters will provide the filaments having the outstanding properties of those of the present invention. Since a word definition of the parameters which define the special group of filaments of this invention would be quite lengthy and unduly complex, the filaments will be described by reference to FIGS. 2 and 3 of the drawings. In view of the fact that four parameters are used in defining the filament cross sections, reference must be made to both of the figures. It should be noted that while the shape of the cross section must remain within the limits set forth in the figures, slight variations in the parameters may occur along the length of the filament as well as from filament to filament in a bundle which do not adversely aifect the novel properties. Accordingly, it is not required that the cross sections exhibit perfect symmetry.

Referring now to FIGS. 2 and 3, the filaments must have an arm angle and a tip radius ratio within the range represented by the area LNVX, and a tip radius ratio and a straight side ratio within the range represented by the area SUCZ. The modification ratio, as previously indicated, must be in the range from about 1.9 to about 4.0.

Filaments having an a tip radius ratio arm angle between about 5 and between about 0.05 and 0.15, a straight side ratio between about zero and about 0.4, and a modification ratio between about 2.1 and 3.0 are particularly preferred since this combination of the parameters provides textile materials having outstanding optical properties.

As previously indicated, spinning conditions used in preparing the novel products of this invention may vary, depending on the particular polymer being spun. In addition, the shape of the spinneret orifice may also be varied. An orifice having a Y-shape or one having a Y- shape with slots along the arms, as illustrated in FIG. 4, may be used advantageously. The dimensions of the orifice can be adjusted to provide filaments of different cross section and deniers. In general, deniers from 1 to 35 are preferred for most textile applications; however, higher denier filaments exhibit the aforementioned novel properties. The optimum denier will, of course, be dictated by the end use of the textile material to be prepared.

The following examples further illustrate this invention.

EXAMPLE I Polyhexamethylene adipamide multifilament yarns are spun using the spinning conditions indicated in Table 1. Relative polymer viscosity of the polymers is determined by the method defined in US. 2,385,890 and is indicated in the table. In each of the samples A, B, C, and D the polymer contains 0.3% TiO as delusterant. The molten polymer is extruded at 291 C. through spinneret orifices with the specific dimensions indicated in Table 1. Each spinneret has 34 holes and produces yarns with 34 filaments. Samples A and B are spun through orifices of the type shown in FIGURE 4, having cross slots in the main arms with the dimensions indicated in Table 1. Sample C is spun through round orifices. Sample D is spun 4 through orifices of the type shown in FIGURE XI of Lehmicke US. Patent 2,945,739, having expanded tips at the ends of the three arms instead of having cross slots on the arms.

The molten filaments solidify as they pass downward through a chimney of moving air, and the yarn is wound up on bobbins. After spinning, the filaments are drawn over a ceramic pin at the draw ratios indicated in Table 1, where draw ratio indicates the ratio of speed of the windup roll to the speed of the feed roll.

The cross scotional configurations of the filaments in each of the samples depends on the configurations of the spinneret orifices. The average measurements of the cross-sectional parameters for each of the samples is indicated in Table 1.

Plain weave taffeta fabrics are woven from these yarns. A twist of 7Z turns per inch is added to the warp yarns before weaving. The filling yarns are woven without further twisting. Loom construction is ends and 80 picks. After scouring and heat setting the finished weight of the fabric is 2.3 ounces per square yard and the fabric has ends per inch and 88 picks per inch. Fabrics A and B have greatly increased cover, crisper and drier hand, and increased color clarity and depth when compared to fabric C. Fabrics A, B and D have high percent light refiectance but fabrics A and B have a more diffuse uniform reflectance than fabric D and have much less sparkle, being relatively free of high intensity light beams.

Table 1 Sample No. A B O D Relativeviscosityolpclymer-.. 45 45 38.-." 38. Orifice type 3-armed 3-armed round. 3-armed with with with crosscrossexslots slots pands. Orifice dimensions, inches: p

Main arn1 Length center of cri- .030..." .020 .015,

free to end of arm. \Vidth .002--. .003 .003. Diameter of expanded .005.

tip of cross arm. Gross arm Distance center of ori- .020.-." .015

ficc to center of cross arm. Length Vidth Chimney Air Flow (ft. /niin.) Windu Speed (yd/min.) 1 Draw .atio a. Yarn Denier (drawn) 75 75 t 70. Cross-Sectional Measurements:

M 3.3 2.4...." 1.7. Angle A (degrees). 26

EXAMPLE II Polyhexamethylene adipamide yarns suitable for use in carpets are melt spun at a temperature of 290 C. through stainless steel spinnerets. Three types of filament cross section are spun for comparison. Table 2 shows the type of orifice, the cross sectional measurements of the filaments, and the amount of titanium dioxide pigment added as delusterant. Sample E is spun through a spinnneret having orifices of the type illustrated in FIGURE 4. The orifices for spinning sample E each have three arms with cross slots similar to the orifices described in Example I for samples A and B. A second cross sectional configuration is spun using the threearrned orifices with expanded tips as described in the Lehmicke patent cited in Example I. A third type of yarn having filaments with round cross section is spun from round orifices.

Each of the samples is spun from spinnerets having 68 orifices. Upon leaving the spinneret, the extruded filaments are quenched in a chimney with an air flow of about 300 cubic feet per minute and are then wound up as 68 filament yarns at a windup speed of 350 yards per minute. The spun yarns are then drawn using a ceramic snubbing pin at a draw ratio sufiicient to give drawn yarns with a tenacity of about 3 grams per denier, and a break elongation of about 35%. The drawn yarn deniers are about 1000. The average cross sectional measurements of the three types of filament are shown in Table 2.

The three drawn yarn samples are each bulked by passing through a jet with superheated steam as described by Breen and Lautcrbach in the copending US. patent, S.N. 698,103, filed November 22, 1957. The singles bulked yarns are twisted 2-Z turns per inch and then three plied with l-S turn per inch.

Carpets having 25 ounces per square yard of pile yarn are tufted from each of the three-ply yarn samples. Carpet samples from E and F have higher total light refiectance than sample G but sample B in addition has greater clarity of color than sample F. Sample E is much superior to sample F in stability to sunlight because of the absence of titanium dioxide pigment. For example, sample B retains its tenacity at a high level for a much longer period of time than during exposure to sunlight than sample F or sample G. In addition, the light-fastness of dyes is much greater in sample E than in sample F. Samples E and F are superior to round cross sections in soil-hiding ability, but the carpet from sample B is significantly better in soil-hiding ability than the carpet from sample F.

EXAMPLE III Samples of polyester filaments are prepared from polyethylene terephthalate containing 0.02% titanium dioxide pigment and having a relative viscosity of 19.5 solution of polymer in 10 parts phenol and 7 parts of trichlorophenol) as described in Belgian Patent 549,179.

The polymer is melt spun at 296 C. through a stainless-steel spinneret of the type shown in FIGURE 4. Upon leaving the spinneret, the extruded filaments are quenched in cross-flor air having a velocity of 65 ft./min. and a temperature of 70 F. and then wound up as a SD-filament yarn at a windup speed of 1500 yards per minute. The total denier of the spun yarn is 170. The spun yarn is then drawn at a temperature of 104 C. using a one-quarter inch ceramic snubbing pin, a draw ratio of 2.5, and a windup speed of 604 yards per minute. The drawn yarn has a total denier of 70, a tenacity of 3.0 grams per denier, and a break elongation of 25%.

The filament cross sections are characterized by the following measurements: r /R is 0.17, angle A is M is 3.0, and f/R is zero.

Taffeta fabric samples prepared from this yarn have a unique combination of attractive subdued luster, high covering power, and excellent color clarity. The fabrics are dry and crisp to the touch.

The filaments of the present invention may be prepared from a variety of synthetic polymers, e.g., polyamidcs, polyester, polyhydrocarbons, polyurethanes, and the like. In addition to these and the representative polymers described in the foregoing examples, the polymers described in U.S. Patent 2,939,201 may be used.

Furthermore, the polyester derived from ethylene glycol and 2.6-naphthalic acid and the polyester derived from 2,2-bis(3,5-dichloro-4-hydroxy phenyl)-propane and isophthalic acid may be used. Similarly, copolymers derived from ethylene glycol, terephthalic acid, and isophthalic acid and copolymers from ethylene glycol, terephthalic acid, and 4,4-bibenzoic acid are useful for preparing the filaments of this invention.

In preparing the filaments of this invention, various known textile adjuvants may be included in the polymer, e.g., pigments, dyes, plasticizers, etc. The filaments may also be subjected to usual after-treatments such as drawing, crimping, bulking, dyeing, etc. As previously indicated, however, the addition of a delusterant is not necessary to obtain a subdued luster. In fact, the addition of any significant amount of delusterant will cause the loss of some, but not all, of the unique properties described. For example, the addition of 0.05% to 0.1% of titanium dioxide will result in a marked reduction in light-stability and dye light-fastncss as well as some loss in optical depth. However, such properties as soiling resistance and covering power will still be retained at higher levels of addition.

Slight variations in the configuration of the filaments may be present without impairing their desirable prop erties. For example, the lobes of the filaments may not be perfectly symmetrical. Other slight distortions may also be introduced into the filament during spinning or processing operations such as drawing, crimping, twisting dyeing, or bulking.

Novel fibers and filaments of this invention may be employed to produce a wide variety of ditlerent types of fabrics including both apparel and industrial textile products. Specific examples of these products include shirtings, suitings, dress and blouse fabrics, hosiery, sheeting, lingerie, tatfetas, georgettes, sand-Crepes, tissue-failles, foulards, broadcloths, batistes, rainwear, surah, tricot, tulles, circular knitted goods, satins, chilfons, sheers, Wash-wear fabrics, crepes, casement fabrics, upholstery, filter cloths, ducks, beltings, webbing, braids, cordage and twine, fiber reinforced laminates, tire cord, coated fabrics, stufiing materials, floor coverings and tiles. The filaments and fibers of this invention are particularly useful in preparing various types of carpeting, e.g., woven, tufted, chenille, Smyrna, Wilton, Saxony, Brussels, velvet, Axminster, orientals, knitted, pleated, and the like due to the particular aforementioned properties which the filaments and fibers of this invention exhibit.

As many widely different embodiments of this invention may be made Without departing from the spirit and scope thereof, it is to be understood that this invention is not to be limited to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. A textile filament of a synthetic polymer having an essentially uniform cross section along its length, said cross section consisting of three integrally joined, substantially symmetrical lobes, said cross section having a tip radius ratio and an arm angle within the range represented by the area LNVX on FIGURE 2 of the drawing, a straight side ratio within the range represented by the area SUZC on FIGURE 3 of the drawing, and a modification ratio within the range from about 1.9 to about 4.0.

2. The filament of claim 1 wherein said tip radius ratio is within the range from about 0.05 and about 0.15.

3. The filament of claim 1 wherein said arm angle is between about 5 and 35.

4. The filament of claim 1 wherein said straight side ratio is within the range from about zero to 0.4.

5. The filament of claim 1 wherein the modification ratio is within the range from about 2.1 to about 3.0.

6. The filament of claim 1 wherein said synthetic polymer is polyamide.

7. The filament of claim 1 wherein said synthetic polymer is polyester.

8. The textile filament of claim 1 wherein the tip radius ratio is within the range from about 0.05 to about 0.15, the arm angle is within the range from about 5 to about 35, the straight side ratio is within the range from about zero to about 0.4, and the modification ratio is within the range from about 2.1 to about 3.0.

9. A textile yarn having a subdued luster comprised of filaments of claim l.

10. A textile yarn having a subdued luster comprised of filaments of claim 8.

References Cited in the file of this patent UNITED STATES PATENTS Taylor Oct. 29, 1889 Brubaker Aug 4, 1942 Shaw May 12, 1953 Terry et al May 22, 1956 Raynolds et al Apr. 1, 1958 Holland June 7, 1960 

1. A TEXTILE FILAMENT OF A SYNTHETIC POLYMER HAVING AN ESSENTIALLY UNFORM CROSS SECTION ALON ITS LENGTTH, SAID CROSS SECTION CONSISTING OF THREE INTERGRALLY JOINED, SUBSTANTIALLY SYMMETERICAL LOBES, SAID CROSS SECTION HAVING A 